From Evan Rodgers on The Verge:

Human Microbiome Project image via The Verge blog.
“Would you be upset to know that you’re coated in bacteria and other microorganisms from head to foot? According to the Human Microbiome Project (HMP), the average adult human’s genome is quite small compared to the “metagenome,” which consists of all of the different organisms both on and inside us….”
If interested in gut flora check out these 2 excellent resources: